Method of manufacturing fibers and films from an acrylonitrile copolymer

ABSTRACT

A METHOD IS PROVIDED FOR MANUFACTURING SHAPED ARTICLES ESPECIALLY FIBERS AND FILMS FROM A SOLVENT SOLUTON OF COPOLYMER COMPRISED OF AT LEAST 85 MOL PERCENT OF ACRYLONITRILE AND AT LEAST ONE OTHER COMPOUND OF THE FORMULA   CH2=C(-CN)-CH(-R)-OH   WHEREIN R IS HYDROGEN, AN ALKYL GROUP, AN ARYL GROUP OR ALKYLARYL GROUP. IN THE METHOD OF THIS INVENTION THE SOLVENT SOLUTION IS SHAPED AND THEREAFTER COAGULATED IN A BATH COMPRISED OF AT LEAST 60% BY WEIGHT OF METHANOL. THE SHAPED ARTICLES, FOR EXAMPLE, FILAMENTS, BECAUSE OF THEIR SUPERIOR PROPERTIES, ARE ESPECIALLY USEFUL AS TEXTILE FIBERS.

June 4, 1974 HIROMU TAKEDA 3,314,739

METHOD OF MANUFACTURING FIBERS AND FILMS FROM AN ACRYLONITRILE COPOLYMER Original Filed Dec. 27, 1971 United States Patent O r 3,814,739 METHOD OF MANUFACTURING FIBERS AND FILMS FROM AN ACRYLONITRILE COPOLYMER Hiromu Takeda, Otsu, Japan, assignor to Toray Industries, Inc., Tokyo, Japan Original application Dec. 27, 1971, Ser. No. 212,374, now Patent No. 3,758,659. Divided and this application Apr. 12, 1973, Ser. No. 350,327

Int. Cl. C0815 15/22 US. Cl. 260-855 R 1 Claim ABSTRACT OF THE DISCLOSURE A method is provided for manufacturing shaped articles especially fibers and films from a solvent solution of copolymer comprised of at least 85 mol percent of acrylonitrile and at least one other compound of the formula CN CH C OH wherein R is hydrogen, an alkyl group, an aryl group or alkylaryl group. In the method of this invention the solvent solution is shaped and thereafter coagulated in a bath comprised of at least 60% by weight of methanol. The shaped articles, for example, filaments, because of their superior properties, are especially useful as textile fibers.

BACKGROUND OF THE INVENTION This is a division of application Ser. No. 212,374, filed Dec. 27, 1971, and now US. Pat. No. 3,758,659.

1. Field of the invention This invention relates to a novel method for producing acrylonitrile copolymer shaped articles.

2. Description of the prior art Heretofore, acrylic fibers from a polyacrylonitrile or an acrylonitrile copolymer have been produced commercially in substantial amounts by wet spinning processes and dry spinning processes. However, in prior art wet spinning processes coagulation is ordinarily accomplished by extruding the polymer ,solution into an aqueous bath which can contain solvents or dissolved salt. As used herein, an aqueous or water bath refers to a composition having water as one of its main components. When the solvent is extracted from the extruded stream of spinning solution in a coagulating bath during wet spinning, solidification of the polymer in filamentary form occurs. Normally, during coagulation there is an inward diffusion of the coagulating bath into the filaments undergoing coagulation, as well as a corresponding outward movement of solvent into the coagulating bath. As is well known, the solvent and bath liquid may interchange in such a manner that the resulting filaments contain microvoids or cavities (see British Pat. 917,290 and British Pat. 950,- 661 and British Pat. 977,943). The filaments containing these microvoids are opaque or dull (hereinafter referred to as devitrificated), and exhibit a delustered appearance, lower tenacity, and lower abrasion resistance as compared with filaments which do not contain microvoids.

' Therefore, to overcome the inherent physical weakness of these coagulated filaments, certain aftertreatment steps have heretofore been conducted during the processing of the filaments tofully collapse the microvoids. The filaments, for example,'were dried at high temperatures. In the wet spinning acrylic filaments, the degree of collapsing of 'the filaments differs depending upon the copolymer composition of the acrylonitrile copolymers, the kind of the solvents, the composition of the coagulation bath and 3,814,739 Patented June 4, 1974 the coagulating conditions. However, unless the coagulated filaments or films are collapsed by drying or homogenization steps, the resulting fibers or films have unsatisfactory properties. In addition, in methods of producing acrylic fibers or films by such conventional wet spinning processes the drawa'bility difiiered according to the collapsing conditions (drying conditions, etc.) of the coagulated filaments or films. Moreover, by secondary processing, for example, dyeing and washing of products, devitrification (the loss of the transparency) is brought about again and the dimensional stability as well as the physical properties change.

Further, when producing acrylic fibers by the conventional wet spinning process, because the fiber-forming method is different from that of melt spinning, it has been found difiicult to produce filaments having a cross sectional configuration corresponding to the shape of holes of the spinneret. Because of this, it has been difficult to control the production process and commercially produce such fibers (for example, see British Pat. 1,191,538).

It is accordingly an object of this invention to overcome the aforementioned problems and difiiculties of the prior art.

Another object of the present invention is to provide a method for a wet system for spinning fibers or forming fibers of acrylonitrile copolymers without requiring a dry collapsing step.

Another object of the present invention is to provide acrylic fibers and films which are substantially void free and transparent, having stabilized physical properties and a very high tenacity and modulus.

A further object of the present invention is to provide a method of producing acrylic fibers or film of acrylonitrile copolymers which can be made with a predetermined cross sectional configuration corresponding to the shape of holes of the spinneret or the extrusion slit.

Other objects and advantages of the present invention will become further apparent hereinafter from a further reading of the specification and subjoined claims.

SUMMARY OF THE INVENTION The objects of this invention have been achieved by spinning or forming an organic solvent solution of an acrylonitrile copolymer obtained by copolymerizing at least mol percent of acrylonitrile with at least one other compound having an alcoholic hydroxyl group, into a coagulation bath containing about 60% by weight of methanol.

BRIEF DESCRIPTION OF THE DRAWING The figure is a photomicrograph of an acrylonitrile copolymer fiber produced in accordance with the process of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with the process of the present invention a method is provided for producing shaped articles such as acrylonitrile copolymers which are compact and excellent in crystallinity, tenacity and modulus. In this method of producing fibers and films of an acrylonitrile (hereinafter referred to as AN) copolymer an organic solvent solution of AN copolymer consisting of at least 85 mol percent of AN and at least one compound represented by the general formula CH1=C OH R Formula I wherein R is a radical selected from the group consisting of hydrogen, alkyl, monoc'yclic aryl, and alkylaryl,

wherein the alkyl group has up to carbon atoms, is shaped and then coagulated in a coagulating bath containing not less than about 60% by Weight of methanol.

The AN copolymers suitable for use in the present invention are known and are disclosed, for example, in U.S. Pat. 3,499,024. However, U.S. Pat. 3,499,024 only relates to the AN copolymers of the present invention, and at best, discloses that such AN copolymers show improved dyeability and absorption property. The prior art does not, however, suggest a method of producing the acrylic fibers or films of the present invention which have improved physical properties.

The use of methanol in a coagulation bath in wet spinning of acrylic fibers is known, and is shown, for example, in Japanese Patent Application Publication No. 511/ 1956. However, when methanol is normally used as a coagulating agent divitrification of the acrylonitrile filaments is remarkable, spinning of filament is difiicult and the physical properties of the filaments obtained are quite poor. Accordingly, methanol coagulation baths have not been used commercially.

In wet spinning, the action of a coagulating agent on the spinning solution varies depending upon spinning conditions, such as the kind of the polymer and kind of solvent used in the spinning solution. Accordingly, the yarn quality of the filaments obtained varies and satisfactory filaments are not necessarily obtained. It has also been found that when wet spinning methods, previously suggested, have been employed that it was impossible to obtain transparent filaments having a cross sectional configuration corresponding to the shape of the spinneret holes.

The compound or mixture of compounds which are copolymerized with the acrylonitrile to produce the acrylonitrile copolymer used in the present invention, is represented by the formula wherein R is a radical selected from the group consisting of hydrogen, an alkyl group having up to five carbon atoms, an aryl group such as phenyl group or an alkylaryl group. Typical compounds which may be used in the present invention are, for example, 2-hydroxymethyl acrylonitrile, Z-hydroxyethyl acrylonitrile, 2-(l-hydroxypropyl) acrylonitrile, 2-(l-hydroxyethyl) acrylonitrile, 2- l-hydroxybutyl) acrylonitrile, 2-(1-hydroxy-2-methylpropyl) acrylontrile and 2-(l-hydroxyhexyl) acrylonitrile. In addition, the AN copolymer can contain as a third component a compound which copolymerizes with AN, such as, for example, acrylic acid, methacrylic acid, and esters thereof, styrene, an a halogenated vinyl compound such as vin'yl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, acrylamide, methacrylamide, an arylsulfonic acid, styrene sulfonic acid and salts thereof.

The ratio of the compound represented by Formula I in the AN copolymer must be at least about 0.01 mol percent, preferably at least about 0.1 mol percent, with the content of the acrylonitrile being at least 85 mol percent. When the amount of the compound shown by the Formula I is less than 0.01 mol percent the compact filaments of the present invention are not obtained and the ability to spin into a coagulating bath is not sufiiciently developed. on the other hand, when the AN con tent is less than 85 mol percent, the desired properties of an acrylic fiber are not obtained.

It is, of course, possible to use mixtures of difierent types of AN copolymers and vinyl polymers within the above noted range, and still achieve the objects of the present invention.

As a solvent for the copolymer of the AN series, it is preferable to use an organic solvent such as dimethyl sulfoxide, dimethylacetamide, dimethyl formamide or a mixed solvent consisting mainly of these organic solvents.

The concentration of the AN copolymer in the solventshould be within the range normally used with, for example, 10-35% by weight being preferable.

The solution of AN copolymer is spun from a spinneret into a coagulating bath containing mainly methanol. The composition of the coagulating bath is not particularly critical, provided it contains at least about 60% by weight and preferably at least about 65% by weight of methanol. When the content of methanol is less than 60% by Weight, transparent and compact filaments are not obtained unless collapsing or homogenization aftertreatments are employed. If the coagulating bath contains at least 60% by weight of methanol, even if said bath contains solvent extracted from the spinning solution or water produced by absorption of moisture, the objects of the present invention can be still achieved.

The temperature and other conditions of the coagulating bath are not particularly critical. However, normally a temperature within the range of 0-35" C. is commercially advantageous because the evaporation rate of methanol is low in this temperature range.

The spinning conditions which are employed, such as, for example, the discharge rate, spinning speed and other conditions, are those conventionally employed in order to obtain filaments.

When the organic solvent solution of the AN copolymer of the present invention, namely, an AN copolymer containing a compound having an alcoholic hydroxyl group is spun into a coagulating bath containing mainly methanol, a very compact coagulated filament is produced without having to be subjected to a dry collapsing or homogenization treatment. This is surprising when it is taken into account, that heretofore when methanol was used as a coagulating bath, for 100% acrylonitrile filament, the amount of devitrification was quite substantial. Even if the filaments were subjected to dry' collapsing, filaments having satisfactory properties were not obtained. In addition, in accordance with the present invention, because dry collapsing is not required, this step can be omitted, which makes the process commercial- I ly feasible and the coagulated filaments can be directly subjected to drawing and heat treatments.

-By the conventional wet spinning of acrylic fibers, unless the filaments are collapsed during the yarn making process, especially if the filaments are spun until they are dry, the filaments are devitrified and it is not possible to obtain good drawn yarn. Moreover, depending upon the coagulation and collapsing conditions, the drawing has to be conducted under specified limited conditions. However, in accordance with the present invention, because the coagulated filaments are substantially voidless, the filaments may be drawn at once. Various drawing means, which employed hot water, hot air, a hot plate, a hot pin, steam or combination thereof can be advantageously employed. Preferably, the filaments are initially drawn in hot water or steam 'and thereafter drawn by a hot plate. Drawing to a high magnification is possible. An additional advantage is that the methanol in the coagulating bath is removed by the hot water or steam before the filaments are drawn by the hot plate, which is commercially advantageous. When the first stage drawing is in hot water or steam, it is advisable to use a low magnification of drawing of an extent such that the methanol in the filament is removed, namely, to draw the filaments at least about 1.5 times at a temperature of at least 10 C. and preferably at least about 50 C. As conditions for second stage drawing'by a hot plate, it is advisable to draw the filaments at least 5 times their length at a temperature of at least about 0 c. and preferably --200 0. t

As mentioned above, in accordance with the present invention, because compact and transparent acrylic copolymer fibers or films are obtained without dry collapsing or homogenization, not only are the process steps simplified as compared with the conventional wet system, but also many of the problemsin quality of the fibers or films produced by the normal collapsing step such as' discoloration and deterioration are avoided. It goes 6 4. An acrylonitrile (99.4 mol percent)2-hydroxyethyl acrylonitrile (0.6 mol percent) copolymer (hereinafter referred to as P(AN-HEN).

5. An acrylonitrile (99.0 mol percent)2 hydroxyethyl acrylonitrile (0.6 mol percent)sodium arylsulwithout saying that in the present invention fibers or 5 fonate (0.4 mol percent) copolymer (hereinafter referred films obtained by a wet process after coagulation may to as P(AN-HEN-SAS).

also be subjected to drycollapsing or homogenization The values of the intrinsic viscosity [1;] of these cotreatments. However, in this case extreme dry collapsing polymers using dimethylformamide (DMF) as the solvent conditions are not required as in the case of conventional 10 are shown in Table 2. In each case, the solution concenwet spinning system and it is accordingly commercially nation was by weight.

feasible. I These copolymers were coagulated from a spinneret Further, in accordance. with the present invention, behaving 200 circular holes each having a diameter of 0.08 cause collapsing of filaments or'films in the coagulation mm. and spun into a methanol bath at a spinning speed bath is excellent, it is possible to obtain filaments or film 5 of 2 m./min. The spun undrawn filaments were therehaving across sectional configuration substantially the after subjected to the four treatments listed in Table 1. sameas the shape of holes in the spinneret or the slit. The following examples are given by way of further It now is, possible to readily obtain filaments having any illustration of the present invention and are not intended shape: including a truly circular cross sectional configurato limit the scope of the invention beyond that of the sub tion which has heretofore been technically difiicult to 20 joined claims. All parts and percentages are parts and obtain by the conventional wet system or a non-circular percentages by weight, not volume, unless otherwise cross sectional configuration and also films having exnoted.

cellent surface smoothness and transparency. For exam- The degree of circular cross section and the X-ray small ple, -in accordance with the present invention, when angle scattering intensity (abbreviated as SASI) appearing spinning is carried out using a s/pinneret in which the in the following examples were obtained as follows.

sha e of the holes is circular, it is possible to obtain filar irents having a substantially circular cross sectional Degree of circular cross section configuration, A photograph of the cross section area of the filaments The, figure 'is a photomicrograph (200 times) showing Was prepared, from which the axial ratio of the cross secthe cross sectional area of coagulated filaments obtained tion of the longer axis, of the cross Section a a b e l f th present i i A can b the shorter axis, b, of the cross section area was of the seen. from the drawing, the cross sectional configuration filaments Obtained- The closer 11/ b is to the close! is of the filaments of the present invention are substantialthe cross Section to circularly truly circular and said filaments are very compact and SASI void free.

With reference to compactness, when the X-ray small Usmg an X'raY Small angle? Scattenng devlce (40 angle scattering intensity is measured, in case of the co- 40 manufactured by Rlgaku Denkl Cow a agulated filaments of the present invention, it is less 10 i was F" from the filaments than 40 counts per second (ch), Which is Surprising and set in the device. Under conditions of a sample disn it taken into account that the intensity of the 40 tance of 26.5 cm and a scatterlng angle of 50', the small conventional filaments, for example, commercially availangle scattermg mtenslty (SASI) was obtamedable filaments of the acrylic series, such as the com- TABLE 1 mercial acrylic fiber Toraylon which is produced in an organic solvent-water bath is at least 150 c./s. Number Treating The filaments obtained by the present invention may 1 ried inairat 20 C-(r00n 1temperature) a be used for clothings and because of the flexibility in the 2 2??33235322? coagulauonwashed mth water at 25 amount of, drawing which can be applied, are also useful 3 g f g g fi g f meguleflm, washed with boiling water invarious industrial application and other applications, 4 After washing with boiling water, dried in air at; 130 0. as will be obvious to those skilled in the art, such as 9 makmg'carbm fibery After these copolymers were treated under the conditions shown in Table l, the X-ray small angle scattering v EXAMPLE 1 intensity (hereinafter referred to as SASI) and degree of Using N,N'-azobisisobutylonitrile (hereinafter referred circular cross section of each undrawn filaments was to as AIBN) as a catalyst and dimethyl sulfoxide (heremeasured. The results are shown in Table 2.

TABLE 2 Concen- SASI Ratio of tration circular of dope, Treat- Treat- Treat- Treatcross Number Kind of polymer percent In] mentl ment 2 ment3 ment4 section 1 PAN 20 1.43 250 290 300 350 0.3

P(ANMEA-SAS) 20 1.42 180 150 210 200 0.5

, 3..- P(ANSAS) 19.5 1.49 190 190 200 190 0.4

4..- HAN-HEN) 20 1.42 40 2o 50 a0 0.9

5--- P(ANHEN-SAS) 19.5 1.43 35 20 50 a0 0. 95

inafter referred tQ-as DMSO) asa solvent, the following polymers were obtained bysolution polymerization:

..,,,1. Bolyacrylonitrile,(hereinafterreferred to as PAN). 5 2. Anacr-ylonitrile (95 .6 mol percent)methyl acrylate (4.0 mol percent)sodium,arylsulfonate (0.4 mol percent)copolymer (hereinafter referred to as P(AN -MEASAS) 3, An facrylonitrile (99.6 mol' percent)sodium arylsul f o nate (0.4 mole percent) copolymer (hereinafter referred to as P(AN- SAS). l i

shown. The number of the sample in Table 3 corresponds to that in Table 2.

From the above Table 3, it can be seen that the filaments of the present invention are definitely superior in tenacity and elongation to the prior art material.

The five copolymer solutions described above were then coagulated in a methanol bath to prepare films having a thickness of 0.08 mm. The obtained films were subjected to the same treatments shown in Table 1 and values of the X-ray small angle scattering intensity were measured. The results are shown in Table 4. It can be seen that the films of the present invention are superior in compactness and homogeneity and excellent in transparency.

Into 4.045 g. of DMSO were charged 4.48 g. of N,N'- azobisvaleronitrile (ADVN), 1.051 g. of AN, 11.5 g. of SAS, 11.7 g. of HEN and 1.07 g. of dodecyl mercaptan. The mixture was polymerized at 50 C. for 20 hours to obtain a polymer solution of P(AN-HEN-SAS) whose [1;] measured at a concentration of 19% by weight at 25 C. in DMF (dimethyl formamide) was 1.52. This solution was spun from a spinneret having 100 circular holes each having a diameter of 0.08 mm. into coagulating baths of the various compositions shown in Table 5. The spinning was carried out at a take-up speed of 2.5 m./min. to obtain 12 denier undrawn filaments.

The obtained undrawn filaments were washed with water (25 C.) and dried in relaxed states at room temperature. The measured results of values of the SASI' and degree of circular cross section of the undrawn filaments 7 TABLE 6 From Table 6 it can be seen that the filaments obtained by using coagulating baths consisting mainly of methanol were compact and had a very good degree of circular cross section. a I

The undrawn filaments were drawn 2 times first in hot water (98 C.) and then in steam at C. immediately after the filaments coagulated. Thejresulting drawn filaments were dried in air in a relaxed state and values of the SASI and degree 'of circular cross section of these filaments were measured. The results are shown in Table From Table 7, it can be seen that filaments other than the filaments obtained from the coagulating baths consisting mainly of methanol were devitrified by the drawing heat media.

' TABLE 7 Hot water Steam Degrees of Degree 0! SASI circular ,SASI circular Number (c./s.) cross section (c./s.) cross section EXAMPLE} As spinning solutions, No. 1 ;of Table. 2 ,(PAN) and No. 5 of Table 2 (P(AN-I:I1EN-SASW)) were used. As coagulating baths, No.1 and No. -6 of Table 5 were used. To draw the filaments :a two-stage drawing was adopted. In the first stage, drawing was carried out in hot water (98 (1.). In the second stage, drawing was carried out onahotplate (165 C.).. ,f v

When hot water was used for first stage drawing, 'it was especially effective for-removing "methanol and the solvent retained in the filamentsfrom the coagulation. In the first stage drawing the filaments were drawn 2 times their origi-' nal length and thereafter the second stage drawing was carried out.

The properties of the obtained drawn filaments are shown in Table 8. It is apparent that by the method of the present invention, the maximum draw ratio became remarkably high and'the obtainedjfilaments had excellent compactness and homogeneity; despite the fact that the prior art collapsing treatment was not carried out. Further, it should be noted, that the drawn filaments produced according to the present invention exhibited excellent yarn characteristics including a tenacity of more than 7 g./d.

I and a Youngfsmodulus; of more than g./d. These are considered-to be due to the fact that a compact and homogeneous coagulated filament is obtained.

- TABLES 7 A I v "Yarn'characteristics I Neat-Max the. 'Drnw- T i Berg? coagu aw ng (maclon a-- I i Polymer lating ratio, ratio; it 'tio n, Young's SASL' r number bath times .times 1. .gjc i. 'percentn modulus "c.-/s.' section 1 6.3 5.1 05331.? 115.3 52 190 0.45 6 5. 1 4. 5 3. 0 49 213 0. 43 1v 12.5 9.3 7.3 n .1931 41 0.98 e 7.1 i 4.0 3.1 j 53 210. 0.45

9 EXAMPLE 4 Using N,N-azobisisobutyronitrile (AIBN) as the catalyst and dimethyl sulfoxide (DMSO) as a solvent, polymers shown in Table were prepared by solution polymerization. The concentration of each of the spinning solutions was made 20% by weight and the spinning solutions were spun from a platinum-gold spinneret having 200 circular holes each having a diameter of 0.08 mm. into a methanol bath to obtain d. undrawn filaments. The spinning speed was 3 m./min.

' The resulting undrawn filaments were subjected to the treatments shown in Table 9. The X-ray small angle scattering intensity (SASI) of each of the samples subjected to these four treatments was measured as Well as the degree of circular cross section and boiling water shrinkage of each of the samples subjected to treatment No. 1 in Table 9. The measured results were shown in Table 10.

As can be seen from these results, the filaments obtained 'by coagulating in a methanol bath an AN copolymer containing at least 0.01 mol percent of a compound such as 2-hydroxyethyl acrylonitrile had no microvoids and had compact and homogeneous yarn qualities. Also, the degrees of circular cross section of the filaments were remarkably high and the cross sectional configurations were substantially circular.

When. the copolymerization ratio of Z-hydroxyethyl acrylonitrile (HEN) exceeded mol percent, the stability of the filaments toward hot water tended to lower suddenly so that it is preferable to make about 20 mol percent the upper limit of the copolymerization amount.

TABLE 9 Number Treating conditions 1 Dried at 20 0. (room temperature) in air. 2 Washed with water at 0. immediately after coagulation TABLE 11 Characteristics of undrawn filaments Measured results of SASI, c./s. Degree Boiling circuwater Treat- Trcat- Treat- Treatlar cross shrink- Solvent ment 1 merit 2 ment 3 ment 4 section age 35 20 40 0. 96 1. 3 34 25 40 38 0.96 1. 2 40 30 52 0. 87 1. 2 70 93 98 98 0. 78 5. 6 s0 91 as 102 0.75 5. 9 83 93 93 108 0. 75 8. 7

EXAMPLE 6 Using N,N'-azobisvaleronitrile (ADVN) as a catalyst, dodecyl mercaptau (DM) as a molecular weight control agent and DMSO as a solvent, a copolymer consisting of 99.0 mol percent of AN, 0.6 mol percent of HEN and 0.4 mol percent of sodium arylsulfonate (SAS) was prepared by solution polymerization. The polymer concentration in the solution was 20% by weight. By adding DM'SO to the solution, polymer solutions having a polymer concentration of 15, 10 and 5% by weight were prepared, and by concentration of said solution, polymer solutions having polymer concentrations of 30, 35 and 40% by weight were prepared. The inherent viscosity of said copolymer was 1.52,

Using these 7 kinds of copolymer solutions as spinning solutions, filaments were spun from a spinneret having 100 circular holes each having a diameter of 0.06 mm. into a methanol bath as a coagulating bath at a takeup speed of 3.5 m./min. The denier of the resulting undrawn filaments was 10 d.

TABLE 10 Copolymerized amount SASI, c./s. Degree Boiling of HEN, of circuwater Kind of mol Treat- Treat- Treat- Treatlar cross shrink- N b r polymer [1;] percent ment 1 ment 2 ment 3 ment 4 section age '2-hydroxyethyl acrylonitrile.

EXAMPLE 5 Spinning solutions were prepared using AN copolymer having an inherent viscosity of 1.58 copolymerizing 0.6 mol percent of 2-hydroxyethyl acrylonitrile (HEN) and using as a solvent DMSO, dimethyl formamide (DMF), dimethyl acetamide (DMAc), ethylene carbonate (EC), propylene carbonate (PC) and nitromethane (NM). These solutions were stable and each had a concentration of 17% by weight.

The solutions were spun from a spinneret having 100 circular holes each having a diameter of 0.06 mm. into a methanol bath to obtain 20 d. undrawn filaments. The spinning was carried out at a take-up speed of 4 m./min. The obtained undrawn filaments were treated same as in Example 4.

As shown in the results in Table 11, it can be seen that DMSO and DMF have especially excellent properties as organic solvents.

When the spinning solution had a polymer concentration which exceeded 35% by weight, spinning was impossible due to gelation of the solution. The resulting undrawn filaments were treated as in Example 4 and values of the X-ray small angle scattering intensity, degree of circular cross section and boiling water shrinkage of these filaments were measured. The results are shown in Table 12.

These undrawn filaments were drawn 2 times in hot water, thereafter values of the maximum draw ratio was measured using a hot pin and a hot plate. At the same time, filaments drawn 12 times were obtained and their yarn quality values were measured. The results were shown in Table 13. When the concentration of the spinning solution was less than 10% by weight, it was found that the yarn quality values were lowered.

TABLE 12 Coneentra- Characteristics of undrawn filaments tion of the spinning Measured SASI values, c./s. Degree of Boiling solution, circular water percent by Treat- Treat- Treat- Treatcross shrink- Nmnber weight ment 1 ment 2 ment 3 ment 4 section age 40 Could not be spun due to gelatio 35 28 35 35 0. 98 1. 2 30 28 30 0. 97 1. 2 20 36 21 40 0. 98 1. 3 15 36 21 39 40 0. 96 1. 2 1o 38 30 39 39 0. 96 1. 2 5 38 38 42 42 0. 95 2. 3

TABLE 13 Concentration of the Maxi- Characteristics of drawn filaments spinning mum Draw solution, draw ratio of Elonga- Young's percent by ratio, sample, Tenaetion, modulus, SASI, Number weight times times ity, g./d. percent g./d. e./s.

EXAMPLE 7 Using ADVN as the catalyst, DM as a molecular weight control agent and DMSO as a solvent, solution polymerization was carried out. The composition of the obtained copolymer contained AN 99.0 mol percent, HEN 0.6 mol percent, and SAS 0.4 mol percent and the inherent viscosity of the obtained polymer was 1.57. The polymer concentration in the polymer solution was 21.3% by weight. 35

The polymer solution used as a spinning solution was spun from a spinneret having 200 circular holes each hav- I claim: 1. The shaped article which is in the shape of a fila- 30 ment comprising a copolymer consisting of (1) at least about 85 mol percent of acrylonitrile and (2) at least about 0.01 mol percent of a compound of the formula ing a diameter of 0.06 mm. into a methanol bath maintained at various temperatures. The denier of the obtained .CHFC 0H undrawn filaments was 15 d. 40 V 4 The spinning states in the coagulating bath at various temperatures and values of the X-ray small angle scatter- R ing intensity as scales of compactness of undrawn filaments were observed and measured. It was found that 31111611 0thectent'ttrlaerature 10: the coaigulating1 bath Svafs less h R d l 1 d f th an e coagu a ing spee was s ow an uslon w erem 1s a ra ica se ec e rom e group conof the monofilaments occurred. At the same time, the s g of y r g a y and y a y said alkyl yarn peeling property lowered. However, the temperature gro p having up to 5 carbon atoms, and having an of the coagulating bath exceeded 30 C., it was found that y small angle scattering intensity f e h the compactness of the undrawn filaments rapidly de- 40 and having tenacity of at least about 7 creased. The results are shown in Table 14. g-/d. and a modulus ofat least g./d.

'r T t M ABLE 14 References Cited I ot t iiifggf SASI UNITED STATES PATENTS ua ee V a tiimm. c./s. Spinning states 55 2,601,659 6/1952 Hearne et a1. 26085.5 A 3,499 024 3/1970 Morita et a1. 260-855 A 15 Th fin 15 180 d fifiiiied. be 3,632,798 1/1972 Morita etal 26085.5A i2 23 HARRY WONG, IR., Primary Examiner i3 23 8 0 U.S- CLX-R.

f; 32 Fusion of the momfilamems 260-308 DS, 32.6 N, 79.3 M, 80.73, 80.75, 80.8, 80.81;

tok 1 sptlgnmggaee at the tune of 264 182, 21oF v 

